In recent years, input apparatus such as operation units, switches and the like having touch sensors such as touch panels, touch switches and the like to receive input operations by operators have been widely used for mobile terminals such as mobile phones, information equipment such as calculators and ticket vending machines, home electric appliances such as microwaves, TV sets and lighting equipment, industrial equipment (FA equipment) and the like.
There are known a variety of types of those touch sensors, such as a resistive film type, a capacitive type, an optical type and the like. However, touch sensors of these types receive a touch input (input operation) by a pressing object (pressing means) such as a finger or a stylus pen and, unlike push-button switches, the touch sensors themselves are not physically displaced when being touched.
As such, there is suggested an input apparatus which includes a control unit for monitoring an input to the touch sensor and, when the input is detected, drives a piezoelectric element via a piezoelectric element control unit to vibrate the touch sensor such that a tactile sensation is provided at operator's fingertip as feedback (for example, see Patent Documents 1, 2).